Really on a roll with my yellow box Lunetta this weekend!
Chanced upon a thing today where I feed an oscillator into pin 1 and the output of a melody generator into pin of a 4070. There was a pot between pins 2 and 3 and the signal to my mixer came out of pin 3. Sounds great! What exactly is happening here?

Here, 4 NAND gates are used, but as is pointed out here, this arrangement of NAND gates gives the same output as a single 4070 (or 4030) XOR gate. I'm not quite sure about the pot between pins 2 and 3. I suppose your feeding the output back into an input, which I haven't tried doing (but it sounds like an interesting idea).

In a true ring modulator, if you feed in two different frequency signals, the output consists of a mix of the sum and the difference of the two frequencies (e.g. 500Hz and 2kHz would give outputs of 2.5kHz and 1.5kHz). These can be mixed with the original inputs, to give a complex sound, which is often like bells, gongs and various metallic objects being hit (especially when you add reverb). The XOR gate produces very similar effects to this, but it's limitation is that it needs square waves to work (it is a logic chip after all). True ring modulators can work with any audio signal inputs.

Acctually XOR is real 100% ring modulation, the effect is exactly the same, but only for digital/square waves._________________As a mad scientist I am ruled by the dictum of science: "I could be wrong about this but lets find out"

Acctually XOR is real 100% ring modulation, the effect is exactly the same, but only for digital/square waves.

Yes, you're dead right JingleJoe. I didn't explain it very well - the "pseudo" was there only because this circuit is limited to square waves. I suppose that you could feed it with any signal that you have "squared up" first e.g. with Tim Escobedo's PWM circuit, or just a hard-driven transistor - I also imagine that this has already been done by somebody .

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